Small Intestinal Bacterial Overgrowth (SIBO)

There’s a lot of talk these days about the importance of friendly bacteria to the gastrointestinal tract. Intestinal microflora, also called friendly flora or probiotics, play a role in regulating the immune system and keeping the colon healthy. However, most of the bacteria in your intestines should be in your colon or large intestines, not your small intestines.

When abnormally large numbers of bacteria (even friendly bacteria) start growing in the small intestines, they actually cause problems with your health. Small Intestinal Bacterial Overgrowth (SIBO) is a condition where abnormally large numbers of bacteria are present in the small intestines.

These bacteria feed off of sugars and starches in the diet (both refined sugars and natural sugars) and produce methane and hydrogen gas. They also inhibit the enzymes in the small intestines that breakdown starches into simple for absorption. This can result in abdominal bloating, belching and/or flatulence (intestinal gas), especially when you eat grains and other complex carbohydrates. The gases produced by these bacteria can also cause abdominal pain, intestinal cramping, and IBS with constipation and/or diarrhea.

Gas pressure in the small intestines can push upwards against the stomach, contributing to the development of a hiatal hernia and causing heartburn, acid reflux, GERD and nausea.

SIBO increase a hormone called zonulin causing an increase in small intestinal permeability (akaleaky gut syndrome), which results in the intestines absorbing large molecules they shouldn’t. The bacteria also like to gobble up essential nutrients like fats, iron and vitamin B-12. The nutrient deficiencies from SIBO along with the absorption of large protein molecules can cause problems with the immune system, and can contribute to allergies, asthma and autoimmune disorders, and a general decline in health.

Other clues that SIBO may be a problem include having better bowel movements after taking antibiotics and having bowel problems get worse when taking probiotics or fiber. If bowel problems began after using opiates for pain, this is another clue that SIBO may be a factor.

Do You Have SIBO?

Experts in SIBO have estimated that about 35-50% of the general public has this problem. Unfortunately, it is not widely understood and hence, is not properly diagnosed. Many people who have SIBO think they have a Candida or yeast infection. However, while yeast overgrowth can occur with or without SIBO, Candida is often overdiagnosed and SIBO is underdiagnosed. Fortunately, the protocols are similar, but the treatment is different enough that people with SIBO may not respond well to a Candida or yeast program and be discouraged by the lack of results.

Medical diagnosis of SIBO is difficult because it is hard to get a culture from the small intestines. There are tests involving collecting breath samples from patients that drink either glucose or lactulose. The lactulose test is the most accurate. These tests must be ordered by a physician.

However, you can also assess this condition fairly accurately by symptoms. If you have an auto-immune disorder, pain in multiple joints, chronic allergies, chronic skin conditions, chronic fatigue or depression or general malaise (just don’t feel good) you may have leaky gut. When you have symptoms of leaky gut coupled with chronic diarrhea or constipation, regular abdominal pain, IBS, bloating or belching after meals, GERD and/or regular indigestion, you may have SIBO.

What Causes SIBO?

There are several major factors that contribute to the development of SIBO. The first is a lack of hydrochloric acid (HCl) in the stomach. HCl helps the body digest proteins, but it also helps to kill bacteria in the food we eat and prevent them from colonizing the small intestines.

A second factor is a lack of intestinal motility. In between meals migrating motor complexes (MMCs) sweep down the intestines, helping to flush bacteria. These movements of the small intestine are what are responsible for what we call hunger pains, the “rumblings” we feel in our gut when we haven’t eaten in a while. These MMCs may be damaged by surgery, intestinal scarring, various diseases, intestinal infections and by certain drugs. Medications that can inhibit these intestinal movements include antibiotics, proton pump inhibitors, antacids and opiates (pain killers) like morphine.

Stress can be a factor in both low hydrochloric acid and the lack of intestinal motility as the sympathetic nervous system (responsible for the fight or flight response) inhibits both digestive secretion and intestinal motility. When we are relaxed, the parasympathetic nervous system is more active and digestion and intestinal motility is enhanced. Unfortunately, many people in our society are eating on the run and do not take time to relax, chew their food thoroughly and enjoy their meals.

A final factor in SIBO is a malfunctiong ileocecal valve. This valve is between the small and large intestines and is designed to prevent backflow (that is, to keep material in the large intestine from migrating back into the small intestine. When this valve is not shutting properly, intestinal bacteria migrate from the colon into the small intestine causing gas, bloating and general weakness and malaise.